1. Field of the Invention
The present invention relates to anti-skid devices for wheels, and more particularly to a means for attaching snow-chains to vehicle wheels.
2. Discussion of the Related Art
It has already been proposed in French Patent reference No. 2,540,443 to use a series of radial arms fixed to anti-skid elements and mutually connected by a ring arranged on the outside of the wheel. This device is intended to prevent the displacement of the anti-skid members relative to the tire.
In addition, German reference No. 3,545,528 discloses anti-skid devices for vehicle wheels intended to be automatically positioned by means of securing members which cause the device to pass from an installation position on the outer side of the wheel to an operating position in which a snow chain is arranged on the peripheral surface of the tire.
In prior anti-skid devices of this type, the snow chain is retained by four arms capable of undergoing rotation relative to the securing members fixed to the wheel during the advance of the vehicle. In the majority of cases, these four arms are sufficient to pull the chain onto the wheel and to lock it solidly on the latter during the advance of the vehicle.
Nevertheless, it has been found that the four arms were not always sufficient to bring the snow chain onto the wheel and to secure it thereon. This defect is particularly frequent in the case of large-diameter wheels, such as wheels for heavy vehicles, since it is possible for the chain to slip between the arms outside the peripheral surface of the tire, or for it to be impossible for the chain to be brought into its position on the peripheral surface of the tire under the action of the restoring members.